The present invention relates to a thermoelectric module using thermoelectric semiconductor elements such as Peltier devices, and in particular, the present invention relates to a thermoelectric module to which lead wires can be readily connected and have a high tensile strength after connection, and wherein can be installed temperature detectors.
FIGS. 11(a) and (b) show the configuration of a typical thermoelectric module known of in the past. Here, FIG. 11(a) is a front view, and FIG. 11(b) is a perspective view. As shown in these drawings, in the conventional thermoelectric module, thermoelectric semiconductor elements 41 are formed from alternating n-type thermoelectric semiconductor elements and p-type thermoelectric semiconductor elements, with the upper surfaces and lower surfaces of the thermoelectric semiconductor elements 41 connected to their respective metal electrodes 42, 43. The thermoelectric semiconductor elements 41 are alternately connected to metal electrodes 42, 43 at the upper surfaces and the lower surfaces, so that all of the thermoelectric semiconductor elements 41 are eventually connected in series. The connections between the upper and lower metal electrodes 42, 43 and the thermoelectric semiconductor elements 41 are performed by soldering. The metal electrodes 42, 43 of the upper surfaces and the lower surfaces are connected to metallized ceramic substrates 44, 45, so that the entire assembly is immobilized as a rigid body.
When a direct current source 46 is connected to the electrodes of this thermoelectric module, and a current flows in the direction from the n-type semiconductor elements to the p-type semiconductor elements, heat is absorbed on the side of the upper electrodes 42 due to the Peltier effect, and heat is generated on the side of the lower electrodes 43. That is to say, as shown in FIG. 11(a), the upper portion of the thermoelectric module forms a heat absorbing side (cold junction) 47, and the lower portion forms a heat generating side (hot junction) 48. When the power source connection direction is reversed, the heat absorption and heat generation sides are switched. By utilizing this phenomenon, the thermoelectric module can be employed in cooling and heating devices. Thermoelectric modules are used in a wide range of applications, from the cooling of LSIs (large-scale integrated circuits), computer CPUs (central processing units), or laser diodes, to refrigerators.
However, thermoelectric modules of the prior art have the drawback that the tensile strength of lead wires is low, since leads for the flow of direct current to the metal electrodes are directly soldered to the metal electrodes.
Furthermore, it may happen that when cooling/heating is carried out using the thermoelectric module, the temperature of the thermoelectric module becomes extremely high for some reason. It has therefore been desired that the thermoelectric module has a means for preventing the thermal destruction of the thermoelectric module by detecting a predetermined temperature and, for instance, cutting off the supply of current thereto prior to destruction of the thermoelectric module. There is also a need to control the cooling side or the heating side to a predetermined temperature when heating/cooling is carried out using said thermoelectric module. To achieve this, it is necessary to accurately measure the temperature of the thermoelectric semiconductor elements. In conventional thermoelectric modules, however, even if one tries to measure the temperature of the contact surface with the lower metal electrode which is the highest temperature portion of the thermoelectric semiconductor element, there is no space to install a temperature detector in the thermoelectric module, so that in actual practice, the temperature of the lower surface of the lower side ceramic substrate is measured indirectly from outside of the thermoelectric module. Accordingly, it is not possible to accurately measure the temperature of thermoelectric semiconductor elements.
An object of the present invention is to provide a thermoelectric module to which lead wires can be readily connected and have a high tensile strength after connection.
Another object of the present invention is to provide a thermoelectric module having a space to install a temperature detector within the thermoelectric module.
A further object of the present invention is to provide a thermoelectric module within which a temperature detector is installed.
The thermoelectric module according to the present invention is provided with a support plate; p-type thermoelectric semiconductor elements and n-type thermoelectric semiconductor elements affixed to the support plate; first metal electrodes connected to first surfaces of the p-type thermoelectric semiconductor elements and n-type thermoelectric semiconductor elements; second metal electrodes connected to second surfaces of the p-type thermoelectric semiconductor elements and n-type thermoelectric semiconductor elements; a first thermally conductive electrically insulating thin film connected to the first metal electrodes; a second thermally conductive electrically insulating thin film connected to the second metal electrodes; and lead patterns formed on end portions of front or back of the support plate for connecting leads of the thermoelectric semiconductor elements. In accordance with this constitution, it is easy to connect the leads of the thermoelectric elements.
Furthermore, the thermoelectric module according to the present invention is such that the first lead pattern is formed on each of the front and back surfaces of the support plate, and a through hole passes through between the lead patterns on both surfaces. A front end of the lead for the thermoelectric module is bent to pass through the through holes and attached by soldering. In accordance with this constitution, it is possible to increase the tensile strength after connecting the lead.
Moreover, the thermoelectric module according to the present invention has a space for installing a temperature detector on the support plate. In accordance with this constitution, it is possible to install a temperature detector within the thermoelectric module.
In addition, the thermoelectric module according to the present invention has a temperature detector installed in the space for installing said temperature detector. In accordance with this constitution, it is possible to provide a thermoelectric module with a temperature detector installed within it.